We will now turn our discussion to how the genetic material contained in DNA is stored and used in cells after it has been synthesized during replication. DNA transcription is the process in which DNA is copied into RNA; as a result the process can also be called RNA synthesis.
RNA, like DNA, is a complex nucleic acid and is used in cells to help synthesize proteins that perform various cellular functions. Transcription is critical because it is a process that helps mediate the expression of genetic material contained in DNA. A DNA sequence provides the blueprint that during transcription is coded into a RNA sequence. The RNA product of transcription then transfers the information from the DNA sequence into a functional protein. Our discussion will follow the three main steps in the transcription process initiation, elongation, and termination--and discuss the molecules and enzymes that mediate the chemical reactions that take place. Our discussion will address the process of transcription in more simple organisms (prokaryotes) as well as in more complex organisms (eukaryotes).